Preventing Symptoms of Depression by Teaching Adolescents That People Can Change: Effects of a Brief Incremental Theory of Personality Intervention at 9-Month Follow-Up

The transition to high school coincides with an increase in the prevalence of depressive symptoms. Could this be due in part to increasing beliefs about the fixedness of personal traits at a time of frequent social setbacks? And could teaching adolescents that people can change help prevent the increase in depressive symptoms? A longitudinal intervention experiment involved three independent samples of students entering high school (N = 599). A brief self-administered reading and writing activity taught an incremental theory of personality—the belief that people’s socially relevant characteristics have the potential to change. The intervention reduced the incidence of clinically significant levels of self-reported depressive symptoms 9 months postintervention by nearly 40% among adolescents assigned to the intervention condition, compared with control participants. Analyses of symptom clusters, measures of self-esteem, and measures of natural language use explored the outcomes that did and did not show treatment effects. Moderation analyses confirmed theoretical expectations. Among adolescents assigned to the control condition, those who endorsed more of an entity theory of personality—believing people cannot change—showed greater increases in depressive symptoms during the year. The effect of this risk factor was eliminated by the intervention.